Overhead traffic informational or directional sign

ABSTRACT

A traffic sign for providing information or direction to drivers of vehicles, which is positioned above a roadway, for example in the roof of a vehicular tunnel, and has a visible lower surface which is substantially parallel or inclined to the roadway surface beneath it and which is formed of translucent material and is illuminated from above, the symbols or lettering of the sign being elongated in the direction of movement of the vehicle, resulting in a condition called anamorphosis.

United States Patent 2,094,436 9/ 1937 Deventer et al. 40/132 2,155,832 4/1939 Hunter 40/125 IUX 2,245,885 6/1941 Webster 40/132 FOREIGN PATENTS 514,291 7/1955 Canada 40/125 10,766 6/1887 Great Britain 40/ l 25 E OTHER REFERENCES Washington Post, Section B, page 1, May 10, 1967 Primary Examiner-Robert W. Michell Assistant ExaminerRichard Carter Attorney-Scrivener, Parker, Scrivener and Clarke ABSTRACT: A traffic sign for providing information or direction to drivers of vehicles, which is positioned above a roadway, for example in the roof of a vehicular tunnel, and has a visible lower surface which is substantially parallel or inclined to the roadway surface beneath it and which is fonned of translucent material and is illuminated from above, the symbols or lettering of the sign being elongated in the direction of movement of the vehicle, resulting in a condition called anamorphosis.

[72] Inventor Joseph R. Campbell McLean, Va. [2]] Appl. No. 649,973 [22] Filed June 29, 1967 [45] Patented Jan. 4, 1972 [73] Assignee SamueIScrivener,Jr.

Washington, D.C.

[54] OVERHEAD TRAFFIC INFORMATIONAL 0R DIRECTIONAL SIGN 7 Claims, 8 Drawing Figs.

[52] U.S. Cl. 40/125 N, 94/l.5, 40/137, 40/132 [51] Int. Cl G091 7/16 [50] Field of Search 40/125, 132,125 D, 125 E, 1251, 125 L, 137; 94/l.5

[56] References Cited UNITED STATES PATENTS 1,539,633 5/1925 Benton et a1 40/125 D 1,709,202 4/1929 Beldin 40/132 mzmem 4:972 3.631.619

SHEET 1 OF 2 TRAFFIC INVENTOR 1- 7- 4 JOSEPH R. CAMPBELL .g mmzfmwm ATTORNEYS mama] JAN 41972 3.831.819

' SHEEIZOFZ INVENTOR JOSEPH R. CAMPBELL leaf/21W M 984M ATTORNEYS OVERHEAD TRAFFIC INFORMATIONAL on nInEc'rIoNAL SIGN SUMMARY OF THE INVENTION It is now common practice to place informational and directional signs directly on the surface of a vehicular roadway by painting or similar marking, typical signs being Left Turn Only, Straight Ahead and the like. It is also common practice, particularly on throughways, freeways and the like to put directional information on vertical, or nearly vertical, signs placed above the roadway. While such signs could be placed along the sides of the roadway, this is unsatisfactory for many reasons and is not a usual practice.

The present invention departs from these known sign positions and arrangements and provides a sign of new construction which is positioned above the roadway and above the vehicles thereon and which has a lower surface which is substantially parallel to the roadway surface or which is inclined longitudinally with respect thereto, and which has letters, words and symbols thereon which provide guidance and other intelligence to drivers of vehicles traveling along the roadway.

A traffic guidance sign as provided by this invention has particular utility for providing informational, directional and other intelligence within a vehicular tunnel, it being most important in certain cases to provide such information within a tunnel in order to prepare the automobile drivers for proper action within the tunnel or upon egress. However, the usual methods of highway signing, which are described above, are not entirely or always satisfactory for tunnel use. For example, horizontal signs painted on the roadway itself are obscured to the drivers vision by the vehicles ahead, particularly in conditions of bumper-to-bumper traffic. Overhead vertical signs are unsatisfactory and are not used as they require substantial additional tunnel clearance height with consequent greatly increased costs of construction and maintenance. Signs along the sides of the tunnel roadway are unsatisfactory for the same reasons which obtain with respect to outdoor use and for the added reason that they would require substantially increased width of the tunnel with consequent added cost.

It has been the principal object of this invention to provide a sign giving direction, information and possibly other intelligence, having a particularly important field of use in vehicular tunnels, which is always visible and cannot be obscured by other vehicles, which requires a minimum increase in tunnel height, or none at all, and no increase in tunnel width, and which is not subject to any of the disadvantages of known signs, such as those described above.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a vehicular tunnel showing a typical traffic informational and directional sign according to the invention;

FIG. 2 is a plan view of the sign of FIG. 1;

FIG. 3 is a sectional view taken on line 33 of FIG. 2;

FIG. 4 is a side view of the tunnel and sign, illustrating the relation of the longitudinal and apparent vertical dimensions of the intelligible part thereof to an approaching vehicle, and

FIGS. 5 to 8 are similar to FIG. 4 and show different forms and positions which the sign according to the invention may take.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 of the drawings there is shown in perspective a section of a vehicular tunnel, having the roadway 2, sidewalls 4,6, roof 8 and egress port 10, an automotive vehicle 12 being shown in progress toward the exit.

Means are provided by the invention for giving directional and other information to the driver of each vehicle within the tunnel. Such means comprise the sign which is supported above the lane 22 of roadway 2 and above the vehicles traveling along that lane. While in FIG. 1 only a single sign is illustrated, providing guidance to the vehicles traveling along a single lane of the tunnel roadway, it will be understood that this is for purposes of illustration only and that each lane or several lanes may, if desired or necessary, be provided with a sign according to the invention. The sign is preferably mounted in or adjacent the tunnel roof 8 and is supported thereby in any suitable manner. In its preferred form, which will be its usual construction, the sign is rectangular in shape and in all forms and embodiments of the invention is substantially parallel or sloping with respect to the roadway and is elongated in the direction of movement of vehicles along the roadway, for a purpose to be described.

The sign itself comprises a rectangular frame having vertical end wall 24 and sidewalls 26,28 which may be of any desired height and may be positioned within the tunnel roof 8 or depend therefrom as shown in FIGS. 1 and 3. The lower surface 30 of the sign, which provides the traffic guidance and informational wording and symbols, is formed of translucent material, which is preferably a plastic but may be another material such as frosted glass, and within the body of the sign are mounted light sources 32 which provide uniform illumination over the area of the translucent sign panel 30. The translucent sign face, when illuminated, should approximate or conform to current acceptable standard signing colors or other required standards such as set forth in ASA D6. 1-1961. The background and the letters and symbols of the translucent panel are preferably contrasting in color or shade and, as shown at 34, the background may be dark and symbols lighter.

In accordance with the invention, the sign itself and the individual letters and symbols thereof are elongated in the direction of movement of vehicles along the roadway lane to which the sign provides information. A typical sign is illustrated in FIG. 2, the direction of traffic movement being shown by the arrow within the sign. The precise amount of elongation of lettering and symbols forming the sign is dependent on certain variable factors, including tunnel height, vehicle speed, and whether the sign face is parallel with the tunnel ceiling or sloping. A minimum elongation factor, assuming the use of current standard signing letters and symbols as set forth in the Manual on Uniform Traffic Control Devices for Streets and Highways (ASA D6.ll96l) would be 2:] for a sloping sign such as shown in FIGS. 7 and 8. For higher speed traffic the recommended elongation factor should be not less than 5:1 with greater elongations at the higher speeds, to the order of l 1:]. The amount of letter or symbol elongation required to create an apparent vertical sign height, dimension x, FIG. 4, for any given distance D, varies with the type of sign face used. For example, the lettering or symbols on a sloping sign face, such as shown in FIG. 8, need not be as elongated as those on a horizontal sign face, such as shown in FIG. 6, to create the same apparent letter or symbol height when viewed from a given distance.

The general rule for determining the apparent vertical sign face height, dimension x, at a given distance D, as illustrated in FIG. 4, is determined by the formula where L the horizontal dimension of the lettered part of the sign,

D the horizontal distance from the vehicle driver to the leading edge of the lettered part of the sign,

x the apparent vertical sign face," which is the vertical distance at the leading edge of the lettered part of the sign between straight lines extending from the dn'vers eyes to the leading and trailing edges of the lettered part of the sign,

(1 the vertical distance between the leading edge and the trailing edge of the illuminated part of the sign,

H the vertical height of the lower surface of the sign above the roadway, and

h the vertical height of the eyes of the driver above the roadway.

As stated above, the translucent lower panel of the sign may be supported below the lower surface of the tunnel roof or may be flush with it. In the preferred embodiment of the invention, which is illustrated in FIGS. 1 and 3, the body of the sign is formed of the depending opaque sidewalls 26,28 and the depending opaque end wall 24 at the trailing edge of the sign. At the leading edge of the sign the lower translucent panel 30 is curved forwardly and upwardly, as shown at 36, to provide an end wall. The shaded background part of the visible area of the sign is preferably surrounded by an unshaded border which is shown at 40 in FIG. 2, and in the preferred embodiment now being described this border at the leading edge of the sign extends across the sign adjacent the lower surface of the roof. I have found that the described arrangement of light and dark areas of the lighted panel of the sign provides maximum clarity and visibility as the sign is approached. While the lighted leading edge of the sign may be upwardly and forwardly curved, as shown in FIGS. 3 and 4, it may be flat and inclined in the direction toward oncoming traffic, as shown in FIG. 5.

While in one preferred embodiment of the invention the body of the sign depends from the tunnel ceiling, with the lighted visible panel below the ceiling, the sign may be positioned within the ceiling itself with the visible panel flush, or substantially flush, with the roof, this embodiment of the invention being shown in FIG. 6.

The lower visible panel of the sign may be horizontal, by which it is meant that it may be parallel to the roadway below it, the invention in this form being shown in FIGS. 1 to 6. However, the lower lighted and visible surface of the sign may be inclined to any desired degree to the horizontal or to the surface of the roadway below it, and such forms of the invention are illustrated in FIGS. 7 and 8. In FIG. 7 the entire sign is below the tunnel roof and the lower visible surface is inclined downwardly in the direction of trafiic movement. In FIG. 8 the visible surface of the sign is inclined in the same way, but the body of the sign is partially within the tunnel roof. The inclination of the lower visible surface of the sign in this manner is found to aid visibility and clarity of the lettering to an approaching vehicle and is especially advantageous for tunnels in which the permissible vehicular speed is high.

It will be understood that while I have described in this specification the preferred forms which the invention may take, such description imposes no limitation on the invention. For example, the background and lettering of the sign may be reversed in shading, in which case the lettering and symbols will be dark and the background light. In fact, any combination of shading and coloring is acceptable and will be determined by local conditions and requirements. Further, while the sign has been described in this specification particularly in connection with a vehicular tunnel, it will be apparent that it is fully susceptible to outdoor installation and use.

I claim:

1. A traffic guidance sign for a vehicular tunnel having a roadway and a roof which has a lower surface above and substantially parallel to the roadway, the sign being located in the roof and having a visible surface which is substantially parallel to the roadway, said surface having intelligible characters thereon which are elongated in the direction of vehicular movement along the roadway.

2. A trafi'rc guidance sign according to claim I, in which the sign is positioned below the lower surface of the tunnel roof.

3. A traffic guidance sign according to claim 1, in which the lower surface of the sign is substantially flush with the lower surface of the tunnel roof.

4. A traflic guidance sign according to claim I, in which the lower surface and leading edge of the sign are translucent and the lower surface is extended upwardly to form the leading edge.

5. A trafi'rc guidance sign for providing information to vehicles moving along a roadway, comprising a body supported above the roadway and above the vehicles thereon, the body having a lower surface which is substantially parallel to the roadway and has characters thereon WhlCh are elongated in the direction of traffic movement, resulting in a condition called anamorphosis.

6. A traffic guidance sign according to claim 1, in which the lower surface is inclined downwardly from the leading edge of the sign in the direction of traffic movement.

7. A traffic guidance sign according to claim 1, in which the apparent vertical dimension x, FIG. 4, of the informational part of the sign in the direction of traffic movement is determined by the formula:

L l- D where L the horizontal dimension of the lettered part of the sign, i.e., that part bearing letters and symbols,

D the horizontal distance from the vehicle driver to the leading edge of the lettered part of the sign,

x the vertical distance at the leading edge of the lettered part of the sign between the straight lines extending from the driver's eyes to the leading and trailing edges of the lettered part of the sign, and termed apparent vertical sign face,

d= the vertical distance between the leading edge and the trailing edge of the illuminated part of the sign,

H the vertical height of the lower surface of the sign above the roadway, and

h the vertical height of the eyes of the driver above the roadway. 

1. A traffic guidance sign for a vehicular tunnel having a roadway and a roof which has a lower surface above and substantially parallel to the roadway, the sign being located in the roof and having a visible surface which is substantially parallel to the roadway, said surface having intelligible characters thereon which are elongated in the direction of vehicular movement along the roadway.
 2. A traffic guidance sign according to claim 1, in which the sign is positioned below the lower surface of the tunnel roof.
 3. A traffic guidance sign according to claim 1, in which the lower surface of the sign is substantially flush with the lower surface of the tunnel roof.
 4. A traffic guidance sign according to claim 1, in which the lower surface and leading edge of the sign are translucent and the lower surface is extended upwardly to form the leading edge.
 5. A traffic guidance sign for providing information to vehicles moving along a roadway, comprising a body supported above the roadway and above the vehicles thereon, the body having a lower surface which is substantially parallel to the roadway and has characters thereon which are elongated in the direction of traffic movement, resulting in a condition called anamorphosis.
 6. A traffic guidance sign according to claim 1, in which the lower surface is inclined downwardly from the leading edge of the sign in the direction of traffic movement.
 7. A traffic guidance sign according to claim 1, in which the apparent vertical dimension x, FIG. 4, of the informational part of the sign in the direction of traffic movement is determined by the formula: where L the horizontal dimension of the lettered part of the sign, i.e., that part bearing letters and symbols, D the horizontal distance from the vehicle driver to the leading edge of the lettered part of the sign, x the vertical distance at the leading edge of the lettered part of the sign between the straight lines extending from the driver''s eyes to the leading and trailing edges of the lettered part of the sign, and termed apparent vertical sign face, d the vertical distance between the leading edge and the trailing edge of the illuminated part of the sign, H the vertical height of the lower surface of the sign above the roadway, and h the vertical height of the eyes of the driver above the roadway. 